1. Field of the Invention
Embodiments of the invention relate to a method of growing a silicon carbide epitaxial film.
2. Description of the Related Art
Compound semiconductors such as 4-layer periodic hexagonal silicon carbide (4H-SiC) are known as semiconductor materials. In producing a power semiconductor device using 4H-SiC as a semiconductor material, a 4H-SiC single-crystal film (hereinafter, SiC epitaxial film) is formed by epitaxial growth on a semiconductor substrate containing 4H-SiC (hereinafter, 4H-SiC substrate), and a SiC single-crystal substrate is produced. Conventionally, chemical vapor deposition (CVD) is known as an epitaxial growth method, for example, refer to Published Japanese-Translation of PCT Application, Publication No. 2009-508799.
In particular, epitaxial growth by CVD grows a SiC epitaxial film on a 4H-SiC substrate by thermally decomposing in a carrier gas, a source gas flowing in a reaction vessel (chamber) and continuously depositing silicon (Si) atoms following a crystal lattice of the 4H-SiC substrate. Typically, monosilane (SiH4) gas and dimethylmethane (C3H8) gas are used as a source gas and hydrogen (H2) gas is used as a carrier gas. Further, nitrogen (N2) gas or trimethylaluminum (TMA) gas is suitably added as a doping gas.